1. Field of the Invention
The present invention relates to an image-forming device. More particularly, the instant invention relates to a user interface apparatus and method for allowing a plurality of users to simultaneously use an image-forming device having a touch screen.
2. Description of the Related Art
A touch screen is designed to execute a command or move a cursor by recognizing a contact point when a user touches the touch screen using a finger or a touch pen having a ballpoint pen shape. The touch screen is a user interface method used in various fields, such as personal digital assistants (PDAs), liquid crystal displays (LCDs), cathode ray tubes (CRTs), banks, authorities, medical equipment, tourism, organization guides, and traffic guides.
In touch screen technology, a pressure sensing method and an electrostatic method may be used. The pressure sensing method is a method of calculating the coordinates of a pressurized location by installing sensors closely together that sense pressure exerted on the surface of the touch screen and sense the degree of pressure when the pressure is exerted. The pressure sensing method is widely used, but its accuracy is low. The electrostatic method has greater accuracy than the pressure sensing method. The electrostatic method calculates the coordinates of a touched location by charging the surface of the touch screen, installing sensors around the touch screen, and sensing the amount of charge lost when touching the touch screen.
Recently, medium or large sized image-forming devices, such as printers or multi-function peripherals (MFPs), generally use a touch screen as a user interface for users' convenience. In general, a plurality of users share such a medium or large sized image-forming device.
However, when operating an image-forming device using a touch screen, only a single user can use the touch screen at a given time. Thus, when a plurality of users want to use the image-forming device simultaneously, all but a certain user must wait to use the image-forming device until the certain user ends his/her work.
Accordingly, there is a need for an improved user interface apparatus and method of using a touch screen which allows a plurality of users to employ the touch screen at the same time.